1. Field of the Invention
The present invention relates to a vehicle lamp. More specifically, the invention relates to a vehicle lamp which can change an irradiating direction into vertically and horizontally optional directions.
2. Related Art
Some vehicle lamps, for example, some headlamps for an automobile can change an irradiating direction into vertically and horizontally optional directions.
In a vehicle lamp described in JP-A-2004-227933, a lamp unit can be supported on a bracket to be horizontally movable and the bracket is supported on a lamp body to be vertically movable, and the horizontal movement of the lamp unit and the vertical movement of the bracket are carried out by using separate driving devices, respectively.
In the vehicle lamp described in JP-A-2004-227933, it is necessary to independently provide a driving device for horizontally changing an irradiating direction and a driving device for vertically changing the irradiating direction. Moreover, the lamp unit is not directly supported on the lamp body but is supported on the lamp body through the bracket. For this reason, the number of components is increased and a cost is necessarily increased with an increase in a component cost and an increase in an assembly man-hour.
In a vehicle lamp described in JP-A-2003-054310, furthermore, the irradiating direction is changed into the horizontal and vertical directions by a driving device using a single driving source. Consequently, it is possible to avoid an increase in the number of components and the assemblyman-hour, thereby reducing a cost.
In the vehicle lamp of JP-A-2003-054310, in a state in which a lamp unit is mounted on an output shaft of a driving device, the output shaft is rotated so that the lamp unit is horizontally swung, and furthermore, the output shaft is moved horizontally in a longitudinal direction so that the lamp unit is swung vertically with an upper end set to be a fulcrum.
In the vehicle lamp of JP-A-2003-054310, accordingly, a weight of the lamp unit is applied to the output shaft and becomes a load to a rotation and a horizontal movement of the output shaft. Therefore, an accurate position control is inhibited. Moreover, an interval between a rotatable support point of the upper end of the lamp unit and a connecting point to the output shaft is varied depending on a horizontal movement in the longitudinal direction of the output shaft. In the movement of the output shaft in a direction in which the interval is increased, therefore, a deviation between a moving locus of the output shaft and that of the connecting point to the output shaft of the lamp unit is an excess load to the movement of the output shaft so that an accurate position control is inhibited.